Signal device for thermostatic switches



April 6, 1948. H. B. Fue-E Er AL SIGNAL DEVICE FOR THERMOSTATIC SWITCHESFiled lay 3, 1944 Patented Apr. 6, 1948 SIGNAL DEVICE rIHERMOSTATICSWITCHES Harry B. Fuge and James W. Blomberg, Somerville, N. J.,assignors to The Singer Manufacturing Company, Elizabeth, N. J., acorporation oi New Jersey Application May 3, 1944, Serial No. 533,856

Claims. (Cl. 2200-121) This invention relates to signal devices and moreparticularly to a signal device for a thermostatically controlledswitch.

Switches of this type are often used on electric motors to break theelectrical circuit to the motor on a rise of current which would beinjurious to the motor. These switches automatically break the circuitto the motor, but in order for the motor to be connected again to theelectrical circuit the switch must be reset manually. One of the objectsof this invention is to provide a signal associated with the switch forindicating that the circuit to the electric motor has been broken by thethermostatic switch and that the switch must be manually reset beforethe motor can again be started.

Another object of this invention is to provide a signal device for athermostatic switch which is built into the push-button of the switchand which does not increase the overall dimensions of the switch. Astill further object of this invention is to provide a combined signaldevice and thermostatic switch which'is economical in construction, easyto assemble and may be built as a unit and applied to the electricaldevice which it is adapted to protect.

With the above and other objects in view, as will hereinafter appear,the invention comprises the devices, combinations and arrangements ofparts hereinafter set forth and illustrated in the accompanying drawingsof a preferred embodiment of the invention, from which the severalfeatures of the invention and the advantages attained thereby will bereadily understood by those skilled in the art.

In the drawings- Fig 1 is a vertical sectional view taken substantiallythrough the center o f .a thermostatic switch having our signal deviceembodied therein.

Fig. 2 is a sectional view taken along the line 2--2 of Fig. l.

Fig. 3 is a top plan view of the device shown in Fig. 1 with thepush-button removed.

Fig. 4 is a side elevation of the push-button showing the lamp encasedtherein.

Fig. 5 comprises perspective views of the push` 2 ing formed withU-shaped slots I4 which are adapted to receive screws for the purpose ofremovably securing the base in the aperture II of the motor casing I0.

The base I2 is provided with holes in which the contacts or terminallugs I5, I6 and Il are placed. The lugs I5, I6 and I'l have their upperends bent over to form fiat contact plates I5', IE and II andelectrically connecting the contact plates I5 and I 6 is a resistanceheater wire 38. A bimetallic disk I8 is disposed within the upstandingwalls of the cup-shaped base I2 and is provided with two contacts I9 and20 on its lower face. The disk I8 is held in position by means of ascrew 2| which is threaded into the base member I2. When heated, thedisk I8 has the characteristic of snapping from the convex positionshown in full lines in Fig. 1 to the opposite convex position shown indotted lines in Fig. 1. However, the disk is unable, upon cooling, tosnap back to its original position and must be moved back manually. Fromthe above it Will be understood that. when the disk is in the positionshown in full lines in Fig, 1, the contacts I9 and 20 are in engagementwith the bent over ends I5 and I'I of the terminals I5 and I'I and theelectric circuit to the motor is closed through the disk I8, and whenth'e disk is in its dotted line position the contacts I9 and 2U are outof engagement with the terminals I5 and II and, consequently, theelectric circuit to the motor is open. The above described switch is oldand well known and further detailed description is deemed unnecessary.

Located at one side of the bimetallic snap-act ing disk I8 and extendingthrough' the reduced portion I I of the aperture II is a push-button 22made of translucent material. The push-button 22 is dome shaped and andis formed with an enlarged laterally extending foot portion 23 which isprovided with diametrically arranged narrow slots 24. Immediately beloweach of the slots 24 is a second slot 25 which is somewhat wider thanthe slot 24. Located within the push-button 22 is a glow lamp 26provided with spaced electrodes 21 and leading in wires 28. The freeends of the wires 28 are soldered or otherwise electrically connected tothe ends of the conductors 29 located within the push-button. Theconductors 29 extend through the slots 24 in the base of the push-buttonand their ends are bent over as indicated at 30 so that they lie alongthe peripheral wall of the foot portion 23. The bent over ends of theconductors are in Contact with the resistors 3| which are embedded inthe inner peripheral 'wall of the cup-shaped base member I2 and are inengagement with the terminals I and I1. Fitted into the lower portion ofthe foot portion 23 is a plate 32 made of insulating material and formedwith diametrically opposed ears 33 which fit into the'slots 25 formed inthe foot portion 23 of the push-button. 'Ihe plate 32 is provided on itslower face with three buttons 34 which are adapted to engage the disk I8and force it from the dotted line position to the full line position toclose the circuit to the motor when the push-button 22 is depressed,From the above it will be understood that the push-button and light maybe built as a unit and applied to the thermostatic switch. l

In order to guide the push-button 22 and prevent it from turningrelative to the base I2, the outer periphery of the foot portion of thebutton is provided with two closely spaced lugs 35which are located onopposite sides of a rib 36 which projects from the inner wall of thecup-shaped base member I 2. This arrangement prevents the push-buttonfrom turning relative to the base and thus maintains the bent over ends30 of the conductors 29 in contact with the resistors 3|. In order tomaintain the push-button 22 centrally of the upstanding walls of thebase "I2 the foot portion of the push-button is provided with a lug 31located diametrically opposite the lugs 35. From the above it will beunderstood that the bent over ends 30 of the conductors 29 and the lugs35 and 31 maintain the push-button 22 in spaced relation with theupstanding wall of the cup-shaped base I2.`

In one use of our improved combined signal device and thermostaticswitch, the switch is applied to an electric motor and if the rotor ofthe motor should stall, or if the motor should be abnormally overloaded,the combined heat from the motor, the resistance Wire 38 and the heatgenerated by the resistance oi.' the thermostatic disk I8 causes thedisk I 8 to snap from the full line position shown in Fig. 1 to thedotted line position. It will be observed that the glow'la'mp 26 is atall times electrically connected to the terminals I5 and I1 through theresistors 3| and electrical conductors 29. However, when the disk I8 isin full line position the terminals I5 and I1 are electrically connectedthrough the disk I8 and as the disk offers considerably less resistanceto the passage of the current than the resistors 3i the lamp does notglow. When the disk I8 snaps to the dotted line position the terminalsI5 and I1 are no longer electrically connected` by the disk and suicientcurrent will pass through the resistors 3| to cause the lamp 26 to glowand thereby indicate that the thermostatic switch has opened and must beclosed before the motor can be started. After the disk has snapped toits open circuit or dotted line position, the push-button 22 may bepushed towards the base I2 so that the button 34 on the plate 33 willengage the upper face of the disk I 8 and iiex the disk so that it willreturn to closed circuit position.

From the above it will be observed that the signal for the thermostaticswitch has been placed within the push-button and that the overalldimensions of the switch have not been increased. It is apparent thatthe above described construction has a wide variety of uses, and it willbe'understood that the form, and arrangement of the several elementsemployed may be eficaces] i y. as may be fairly embodied within'b thespirit and scope of the appended claims.

Having thus set forth the nature of the invention, what we claim hereinis:

-1. In a `thermostatic device having a basemember carrying spacedterminals anda heat responsive snap acting bimetallic disk bridging thespace between the terminals and having an initial circuit closingposition and an open circuit position to which it moves by thermalaction, the improvement which comprises the provision of a push-buttonlocated on one side of said disk for moving said disky from open circuitto closed circuit position, resistance elements embedded in said basemember and in electrical contact with said terminals, conductors carriedby said push-button and slidably engaging said resistance elements, anda glow lamp disposed within said button and electrically connected tosaid conductors.

2. In a thermostatic device having a basemember carrying spacedterminals and a heat responsive snap acting bimetallic disk bridging thespace between the terminals and having an initial circuit closingposition and an open circuit position to which it moves by thermalaction, the improvement which comprises the provisions of a push-buttonmade of translucent material and located on one side of said disk formoving said disk from open-circuit to closed circuit position, twooppositely disposed resistance elements in electrical contact with saidterminals, conductors carried by and movable with said pushbutton, saidconductors having a sliding engagement with s'aid resistance elements,and a signal lamp disposed within said push-button and electricallyconnected to said conductors.

,3. In a thermostatic electric switch comprising a base-membercarryingspaced stationary electrical contacts, a heat responsivesnap-acting disk located on one side of said contacts and adapted toengage said contacts in normal circuit closing position and to move awayfrom said contacts to an open circuit position upon an abnormal rise intemperature, the improvement which comprises the provision of a pair ofspaced resistors electrically connected to said contacts,

a push-button located on the side of said disk opposite to the contacts,conductors carried by said push botton and contacting said resistors,

' and a signal light carried by said push button contacts to an opencircuitrposition upon an abnormal rise in temperature, the improvementwhich comprises the provision of a pair of -spaced resistorselectrically connected to said contacts. a translucent hollowpush-button located on the side of said disk opposite to the contacts, vsaid push-button being confined to a right line movement, electricalconductors passing through the Walls of said push-button and havingtheir extending ends in engagement with said resistors, and a glow -lamplocated within the hollow pushbutton and electrically connected to saidconductors.

5. In a thermostatic electric switch comprising a base-member carryingspaced stationaryelectrical contacts, a heat-responsive snap-acting disklocated on one side of said contacts and adapted to engage said contactsin normal circuit-closing position and to move away from said contactsto an open circuit position upon an abnormal rise in temperature, theimprovement which comprises the provision of a pair of spaced resistorselectrically connected to said contacts, a hollow push-button located onthe side of said disk opposite to the contacts, said push-button beingconned to a right line movement, electrical conductors passing throughthe walls of said push-button and having their free ends in engagementwith said resistors, and a glow-lamp located within the hollowpush-button and electrically connected to said conductors.

HARRY B. FUGE.

JAMES W. MOMBERG.

6 REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 506,729 y Rex Oct. 17, 18931,184,234 Goehrend May 23, 1916 1,985,276 Brach Dec. 25, 1934 2,199,388Bolesky May 7, 1940 2,234,954 Bergman Mar. 18, 1941 2,246,613 BigmanJune 24, 1941 2,276,785 La Mar Mar. 17, 1942 2,293,179 Swingle Aug. 18,1942

